The taskbar itself is what is being referred to, I believe. Having the taskbar mounted to one side of the screen allows for a bit more vertical space to be used by apps, which is pretty nice on aspect ratios that limit vertical space, i.e. 16:9. It’s the way I currently run my taskbar and I can’t really imagine having to use it locked to the bottom of the screen.
I think they want a vertical bar versus horizontal, I prefer this setup for laptops too, e.g. I have the dock on macOS on the left and Ubuntu/Gnome it is the default. It makes a huge difference when vertical screen estate is at a premium, as is the case with many laptops.
I would too but mac does it in a pretty annoying way compared to say ubuntu unity.
With multiple monitors, it snaps to the side most one you have plugged in regardless of your primary screen.
I get there's a lot of dragging and dropping involved with the bar, but in Unity it let you set a threshold for mouse speed to limit you going to another monitor.
Just let me put it on the side and do that if I'm dragging something, it's not too difficult.